Stem and Stem Leaf Cells: Outermost cortical cells swollen and fine-walled, usually in 2-3 tiers occasionally patches may be only 1-tiered (FNA 2007), those on the external surface usually with one pore at their distal end (Smith 1980). Hyaline cells of the stem leaves not partitioned, the outer (convex) leaf surface showing an abundance of tiny pores lined up uninterruptedly along the margins juxtaposed to the green cells, the concave (inner) leaf surface lacking a display of pores or showing a small number of pores sprinkled along the cell margins and at the ends of the cells.

Branch and Branch Leaf Cells: Branch stems enclosed by 1 layer of swollen, fine-walled retort cells that lack fibrils and are typically intermixed with rectangular cells that lack pores. Hyaline cells of the branch leaves like those of the stem leaves, fibrillose; green cells in X-section exposed similarly on both surfaces or slightly more at the convex leaf surface (FNA 2007), occasionally just barely hidden at the concave surface, barrel-shaped (Smith 1980), the end walls of normal thickness (FNA 2007).

Phenology

Fruit ripens the last part of spring into the first part of summer (FNA 2007).

Diagnostic Characteristics

Size and branch clusters variable, with some plants unforked and others with as many as 3 branches in each fascicle. Recognition is aided by the paucity of pendent branches, which reveals the spreading stem leaves (FNA 2007).

Range Comments

North American Range

Canada: YT, and most provinces of the southern tier; USA: northeastern states s to NY, also OH, IN, MI, WI and MN, and the western states of MT, WY, CO, OR, CA and AZ (FNA 2007). Known in Montana from Meagher and Park Counties (Elliott 2016).

Habitat

Minerotrophic environments, such as lake and stream margins, and fen margins, particularly if there is a periodic flooding of nutrients (FNA 2007); wet soil and peat (Elliott 2016).